Transformer windings



oct. 2 1, 192s.

H.I L.. coLQE TRANSFORMR WINDINGS Filed Aug.. 6, 1923 POWER suvpuen BY A TAKEN BY Bac 15 leakage reactance therebetwe Patented oa. 2r;9 1925.Y

A rssai AuruTiio STATES PATENT OFFICE.

HORACE L: COLE, F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGH-OUSE .ELECTRIC MANUFACTURING COMPANY, A CORPORATION 0F 'PENNSYIIV'ANIA` rniiNsronMnn wrixfnmes.

.imiucatmn med August e, 1923, serial nu. 655,839.

To all fwwm t may concern: l

Be it known thatI, HORACE L. Conn, a citizen of the United States, and a resident ofWilkinsburg, in the countyof Allegheny 5 and State of Pennsylvania, have invented a new and useful Improvementin Transformer Windings, of which the following is a specification.

My invention relates to transformers and more particularly to an arrangementlof windings therefor. f

One object of my invention is' to provide a transformer in which the several windings are divided in such manner that the l en is substantially zero, at definite points., y k

It is another object of my inventionjto yprovide a transformerrin which a plurality of series of coils are so placed relativelyto each other that the resultant magneticl reactance between the severalgroups of windings is substantially zero. y

It is also an object of my invention to provide a transformer in which a plurality of windings are divided into series of coils so arranged that the total. distance `from the coils in' any one series to the coils in any other series is substantially equal.

In transformers provided with a `plurality of series of coils, each of which series is adapted for generating a particular voltage, it has been found that the reactance between the several series of coils is often times suficient to cause mechanical and elecu trical breakdowns between the various coils of. the transformer with a resulting liability to short-circuiting andN tlieeom panying dangers of explosionand tire. In order to neutralize the reactance between- `sarthe several series of coils, I propose to make each; coil of substantially the same electrical capacity and to so place the several coils comprising the sing-. Q series at substantially equal distances from the coils of the other series. It is apparent that the resulting reactance' between thercspcctive pairs of series of coils is leakage reactance produced by all the series of coils is substantially zero.

In the accompanying drawings,

Finne i is a diagrammatic illustration oi an arrangement of transformer coils embodying my invention applied to a transi'oriner naving three series of windings.

equal and the resultantl x the transformer.

:the

vention, as shown in Figs.

Y C. Each of these series' is Figs. 5 and 6 are similar curves showing thel relations ybetween the different series of coi s.

Fig. 7 is a curve illustrating the distributof. the magnetomotive force throughout transformer when one series of coils is energizing a pair of series of coils.

In the preferred embodiment of my in- 1 and 2, I procoils A, B and vide' a plurality of series of three coilsv which are mounted on any suitable ,core `member 1. A second system of coils (not shown) may also be mounted on the core member l. Each series of coils represents the several systems of windings which are customarily placed in atrans- :former structure, whereby the same transformer structure may be adapted to a plurality of voltages. My invention is applicable to transformers having at least lthree systems of windings. Each of the coils, comprisin V the several series, are of substantially the same electrical capacity, although either the number of amperes or the nimber" ofturns''inay not be the same as in the adjacent series of coils. While the iigures represent the well-known shell type of construction of the core member, ,the invention is equallyapplicable to the core type,

vor any type which employs the interleaved coil construction for the windings. y The invention is not limited to single phase trans-- formers, but is equally adapted for multiphase transforiners.l y

The term reactance, as employed in this application, yis understood to refer tothe electromagnetic leakage which takes place between the several systems of windings which are active when the transformer is carrying normal load. There is also an electromagnetic leakage within active coils themselves, but this factor is usualiy subdivided into.

susY

' tems of'windings can be made substantially equal to that between any other two systems of windings, or can be made, within reasonable limits, any' desired value.l

The distance between the faces of any two adjacent coils is d1, andthe distance be-i tween the adjacent face otone coil and the adjacerdnface of the third coil is represented Y by the distance 032, and the distances between the end coils of adjacent groups comprising a coil from each ofthe groups il, B and C is represented by 0.- F rom this arrangement it follows that the total distance between the several windings of the series A and the series B equals Qdl-l-dg-l-Qo. Similarly, the distance between the coils in the series B and the series :C to A equals Qdli-l-dz-l-Qlo. By reason of the `fact 'that the several coils of each group are ot the same or substantially the same ampere.` turns, there will be no magnetomo'ti've force and, consequently, no leakage reactancey across the distance o.

This feature is diagrammatically shown in Figae, 5 and 6 which are laid out to scale in accordance with the structures shown in Fig. 1. Fig.A 4 shows the magnetomotive orce which exists between the coils A and B throughout the' transformer. lig. 5 shows similar,V relation between coils A and C and Fig. 6-shows the relation between the coils B and C. Fig. Y' shows the niagnetoinotive torce ,.which existswhenV the series of coils A isl utilized for energizing the series of coils B and C. lt is to be observed that in all of these cases, the magnetornotive force at the points corresponding to the spaces o in Fig. l is Zero. lhis relation holds true for any combination of the windings.A

ln view of this relation between the sev- 'eral groups of windings, the distance over which there is'effective magnetomotive 'force between the windings of each series may be written 2051+022. The arrangement ot the coils in eachgroup, as shown in Fig. 2, tollows the saine mathematical formula ex- A cept that their order is varied.

ln the arrangement of coils shown in Fig. 3, there are four series of coils A., B, C and l), and each group of' coils represent one coil airone each of the series'A, B, C and l).

The distance between the adjacent faces ot any two coils in each group is indicated 'by all. The distance between the adjacent` faces or' the first and thirdcoils is indicated by d2', and the distance between the adjacent faces of ed by d3. The distance between the several groups of coils is indicated aso.

i 7lhe distance between any two series ot windings over which there is edective inagp netoinotive i'orce is equal to fl-lfQd-led".

lt will thus be seen that in a four-winding Jtransformer embodying my invention, there are six different groups of coils, the totalv reactance between any two series'ot windings being substantially the saine.

My scheme may be enlarged indeinitely, and the total reactance between any two series of windings will remain lthe same. lhe formula for distance between any two the first and fourth coils is indicatseries of windings, across which there is effective magnetomojtive force, may be Written as Y 'l have, therefore, provided a transformer in which the several coils comprising each` major winding are so placed relative to the coils of the other windings as to produce substantially a zero magnetomotive torce between any two groups of coils, and, in addition, aptransformed in which the reactance between any two series of coils is. substantially the same. i

I have not overlooked the fact that in the actual design and construction, where taps ,0G

in the-windings 'for slightly reduced orincreased voltages are required, or for other electrical and mechanical reasons there may be a very small magnetomotive `torce across thespaces 0 o, between the groups, which, for practical purposes will be substantially zero iti-comparison with the other magnetoinotive forces involved.

l do not'wish to be restricted to thesis/1K] ciccircuit connections or4 arrangement of .parts herein set forthfasfva/rious modifications thereoi/iay be Veffected within the spirit and scope of my invention. l desire, therefore, that only such limitations shall be imposed as are indicated inthe appendedi claims. v Y 'f i I claim as my invention: A'

l. ln an electrical device, a core member, three or more series ofl coils thereon, said series of coils being so placed relative to one another that substantially equal distances,

across which there is a magnetomotive torce which produces leakage reactance, exist between the coils or'. any one series andthe coils of any other series.

2. ln an electrical device, a core member, three or more series of coils thereon, the several coilsc each series being so placed' rela# tive tothe coils of the other Series that the total leakage reactance between any two series of coils is substantially equal' to the total leakage reactance between any other two series. l

3. In an electrical device, three or more series of coils, the coils of each series being placed between the -coils of the other series, whereby the resultant magnetomotive force producing leakage reactan'ce between `all of the' coils is substantially zero.

4. In an electrical device, a core member,

three -or more' series of coils thereon, the.

coils of each series being so placed relative to the coils of the other series that the'total eli'ective distance across which there is a magnetomotive force which produces leale,

age reactance, between the coils of any two series correspond to i 5. In an electricalldevice, a. core member,

three or more series of coils thereon, adapted for energizing one another, the coils ot eachseries being so placed relative to the coils of the other series that the total eii'ective distance, across which there is a inagnetomotive force which produces leakage reactance, between the coils of any'two series is substantially equal to the total eiiective distance between the coils of any other two series.

vseries'of coils, each of said coils being of substantially the same electrical capacity, the coils of each of said series being so placed relative t the coils of the other series that the total effective distance, across which there is a magnetomotive force which produces leakage reactance, between one yseries of coils andvanother series ofcoils vis substantially equal tothe total effective disf tance between any other two series.

8. In an electrical device, three or more series of coils, "each of said coils beingv of substantially the same electrical capacity, each of said series being so subdivided and placed relative to the coilsofvthe other sew ries that the magnetomotive force or leak? age rcactance at definite points in said electrical device i" substantially zero.

In testimony whereof, I have hereunto HORACE L. COLE.

Certificate of Correction.

It is hereby certiiedthati in Letters Patent No. 1,558,841, granted October Q7. 1925, upon the application of Horace L. Cole, of IVilkinsbi/irg, Pennsylvania, foi

an improvement in Transformer IVindings,

an error appears in the printed specication requiring correction as follows: Page 3, at the end oi' claim 4 strike out the equation, and insert the following instead:

(n- 1 d1+ (www (wenn- +3d 3) +Mw, +d(,;,.; and that the said Letters Patent should be read 'with this correction therein that the same may conform to the record of the case in the Patent Olice.'

Signed'and sealed this 15th dayvo'f December, A. l). 1925.

IVM. A. K1N N AN, Acting (."ommlssz'oner of Patents.

subscribed my name this 2nd day of August, 

